It
was not so long ago that switches were used in telecommunications primarily for
placing telephone calls. Dialing a telephone number activated a series of switches
to set up a voice path that could be as simple as the next office or as complex
as a multinational conference call. Internetworks and the Internet are beginning
to provide similar services for PC workstations, servers, and mainframes. The
primary goal of any data network provider is to eliminate geographic and media
constraints on connectivity while maintaining control over resources and costs.
Embedding Layer 3 Switching into the network is being promoted as the best way
to achieve this. A variety of
switch and router technologies are entering the market and creating confusion
among network professionals. New terms such as Layer 3 switching, multilayer switching,
routing switch, switching router, and Gigabit router are clouding the traditional
distinctions between switches and routers.

Furthermore, many wiring closet switches
that traditionally employed simple Layer 2 switching are now offering Layer 3
switching functions or future options for Layer 3 capabilities. These changes
make it difficult for network designers to understand and deploy effective network
solutions. It is clear that a
new generation of Internet and intranet work processes are emerging and that users
will benefit from both increased competition and new services. It is therefore
important do demystify the hype and understand when and where Layer 3 switching
is important by getting back to the basics.Layer
3 switches are compared to traditional multiprotocol routers. It is demonstrated
that Layer 3 Switching is simply a re-invention of the router using new switch
based technologies. This seminar also reviews the basic data forwarding, route
processing, and value-added functions that are required of any intelligent network
node.